Energy Conversion Devices Research Articles

Enhanced Electron Emission Performance and Air-Surface Stability in ScO-Terminated Diamond for Thermionic Energy Converters.

Diamond with negative electron affinity (NEA) and low work function surfaces are suggested as a suitable material for electron-generation applications in vacuum, in particular, as the emitter electrode in thermionic energy converters. Such NEA surfaces can be fabricated by evaporating and then annealing submonolayers of a suitable metal in vacuo onto bare or oxidized diamond. Among the metals studied, scandium termination of bare diamond (100) and (111) surfaces is recently reported to give the largest NEA values reported to date for a metal-diamond system, as well as being thermally stable to 900°C. It is now shown that preoxidized (100) diamond functionalized with 0.25monolayers of Sc also produces a large NEA value of -1.02eV with low work functions (<3.63eV). Moreover, this surface is thermally stable to 700°C and can withstand exposure to air for extended periods. Here, the structural and electronic properties of this Sc─O-functionalized diamond surface are characterized in detail using a variety of surface-science techniques. The results suggest that this material may be the ideal candidate for the fabrication of commercial thermionic energy conversion devices, e.g., for solar-power generation, as well as for various other electronic devices that rely upon electron emission.

Fabrication of bio-abiotic hybrid living hydrogel for bifunctional electrochemical conversion

Design and intelligent use renewable natural bioenergy is an important challenge. Electric microorganism-based materials are being serve as an important part of bioenergy devices for energy release and collection, calling for suitable skeleton materials to anchor live microbes. Herein we verified the feasibility of constructing bio-abiotic hybrid living materials based on the combination of gelatin, Li-ions and exoelectrogenic bacteria Shewanella oneidensis manganese-reducing-1 (MR-1). The gelatin-based mesh contains abundant pores, allowing microbes to dock and small molecules to diffuse. The hybrid materials hold plentiful electronegative groups, which effectively anchor Li-ions and facilitate their transition. Moreover, the electrochemical characteristics of the materials can be modulated through changing the ratios of gelatin, bacteria and Li-ions. Based on the gelatin-Li-ion-microorganism hybrid materials, a bifunctional device was fabricated, which could play dual roles alternatively, generation of electricity as a microbial fuel cell and energy storage as a pseudocapacitor. The capacitance and the maximum voltage output of the device reaches 68 F·g-1 and 0.67 V, respectively. This system is a new platform and fresh start to fabricate bio-abiotic living materials for microbial electron storage and transfer. We expect the setup will extend to other living systems and devices for synthetic biological energy conversion.

Boosting hydrogen production via alkaline water splitting: Impact of Ag doping in Gd2O3 nanosheet arrays

Hydrogen is a preferable renewable energy carrier in decarbonization efforts to develop sustainable and carbon-free economies due to its high energy density and absence of pollutant emissions during combustion. Among others, electrochemical water splitting (EWS) is a sustainable and eco-friendly technology for producing green hydrogen, representing an essential initial step towards achieving carbon neutrality. In this study, we synthesized a bifunctional electrocatalyst by vertically anchoring Ag-doped Gd2O3 nanosheet arrays onto a three-dimensional nickel foam (NF) substrate. The developed materials were thoroughly investigated using various analytical techniques. Furthermore, the electrocatalyst effectively performed oxygen evolution reactions (OER) and hydrogen evolution reactions (HER). The Ag4%-Gd2O3/NF exhibited boosted HER activity, achieving higher current densities ranging from 10 to 400 mA cm−2 at an overpotential between 14 and 122 mV. This study also highlights the considerable impact of metal sites in both Ag4%-Gd2O3/NF and Gd2O3/NF on the HER catalytic process. Similarly, the Ag4%-Gd2O3 electrocatalyst exhibited superior OER activity, with an overpotential of 209 mV at 10 mA cm−2. The optimized composition also shows Tafel slope of 25 and 20 mVdec−1. Furthermore, Ag4%-Gd2O3 demonstrated the ability to generate oxygen gas bubbles in approximately 20 h for OER, making it an attractive material for energy conversion and storage devices.

Deep learning performance prediction for solar-thermal-driven hydrogen production membrane reactor via bayesian optimized LSTM

The random fluctuation of solar energy poses significant challenges for direct solar utilization systems. Solar-driven membrane reactors (SMMR) are efficient devices for energy conversion and pure hydrogen production, featuring thermal inertia and complex physicochemical processes. To realize advance control of SMMR under solar variations to promote their practical application, accurate performance prediction is essential. This study develops a deep learning-assisted performance prediction model for SMMR using Bayesian optimized long short-term memory (BO-LSTM) network and weather classification. Time-series datasets with similar environmental features are generated through SMMR multi-physics modeling and trained by BO-LSTM. The BO-LSTM demonstrates high accuracy in both short-time (1-day) and long-time (40-day) predictions, with a correlation coefficient exceeding 0.997 and a deviation of ±0.0016 in long-term predictions. Weather classification ensures consistent prediction accuracy across different weather. Compared to RF, SVM, BPNN, and CNN models, BO-LSTM provides smoother prediction curves and significantly improves accuracy and stability, reducing RMSE by 44.6% on sunny days and 53.3% on cloudy days in short-time predictions, and by 56.7% and 68.0% in long-time predictions, respectively. The BO-LSTM proposed in this study accurately predicts SMMR performance under various weather, guiding practical applications and offering a reference for prediction and control in solar thermal utilization systems.

Harnessing PbZrO3-Polymer composites for enhanced electron collection through advanced interfacial engineering

The integration of metal oxide-polymer composites into energy conversion devices presents a promising strategy for improving electron collection efficiency. This study addresses the performance challenges faced by Dye-Sensitized Solar Cells (DSSCs), particularly in enhancing light absorption and charge carrier transport. The investigate the use of hybrid PbZrO3-Polymer composites, specifically PbZrO3 Perovskite combined with PNMPy-PoA conducting polymers, to optimize electron collection in these devices. Utilizing advanced characterization techniques, including structural analysis, morphological studies, and electrochemical measurements, Author explore the synergistic interactions between the metal oxides and polymers. By incorporating PbZrO3 nanoparticles with conducting polymers (poly-o-anisidine and poly-N-methyl pyrrole) and organic DTTCY dyes, synergetic achieves a significant improvement in the power conversion efficiency (PCE) of DSSCs. Our results reveal that the optimized PNMPy-PoA-PbZrO3 counter electrode exhibits a photoelectric conversion efficiency of 3.46 % under ideal conditions, with reduced charge transfer resistance at the electrolyte-counter electrode interface. These findings highlight the effectiveness of hybrid metal oxide-polymer composites in enhancing electron collection and stability, offering substantial improvements in the performance of energy conversion devices.

Phosphor-doping modulates the d-band center of Fe atoms in Fe-N4 catalytic sites to boost the activity of oxygen reduction

Regulating the electronic structure by phosphor-doping is a preferred strategy to boost the performance of carbon-based catalysts for oxygen reduction reaction (ORR). Here, a porous Fe, P, N-codoped carbon catalyst (PCF-FeTz-900) is designed by a phytic acid-assisted thermal etching strategy, in which P atoms are first doped into the carbon matrix to form a stable PC bond, and then FeN4 sites are produced from Fe-2,4,6-Tris(2-pyridyl)-s-triazine complex (Fe-TPTz). Theoretical calculations suggest that the electrons are transferred from the doped P atom to the neighboring FeN4 sites, which facilitates the ORR at the Fe sites by reducing the energy barrier and the adsorption energy of intermediates. Additionally, the P-doped FeN4 (FeN4P) structure manifests a lower free energy difference than that of FeN4 and the d-band center of Fe is also lowered, which further ensures its higher ORR catalytic ability. As a result, the PCF-FeTz-900 catalyst exhibits superior ORR activity and stability in alkaline electrolyte, and the assembled primary zinc-air battery shows greater performances compared to the commercial Pt/C catalyst. This work can provide an effective pathway for modulating the performance of doped-carbon materials in energy conversion devices.

Developments in Nanostructured MoS2-Decorated Reduced Graphene Oxide Composite Aerogel as an Electrocatalyst for the Hydrogen Evolution Reaction.

Developing lightweight, highly active surfaces with a high level of performance and great stability is crucial for ensuring the dependability of energy harvesting and conversion devices. Aerogel-based electrocatalysts are an efficient option for electrocatalytic hydrogen production because of their numerous benefits, such as their compatibility with interface engineering and their porous architecture. Herein, we report on the facile synthesis of a nanorod-like molybdenum sulfide-reduced graphene oxide (M-rG) aerogel as an electrocatalyst for the hydrogen evolution reaction (HER). The 3D architecture of the network-like structure of the M-rG hybrid aerogel was created via the hydrothermal technique, using a saturated NaCl solution-assisted process, where the MoS2 was homogeneously incorporated within the interconnected rGO aerogel. The optimized M-rG-300 aerogel electrocatalyst had a significantly decreased overpotential of 112 mV at 10 mA/cm2 for the HER in alkaline conditions. The M-rG-300 also showed a higher level of reliability. The remarkable efficiency of the HER involving the M-rG-300 is principally attributed to the excellent connectivity between the rGO and MoS2 in the aerogel structure. The efficient interconnection influenced the achievement of a larger electrochemically active surface area, increased electrical conductivity, and the exposure of more active sites for the HER. Furthermore, the creation of a synergistic effect in the M-rG-300 aerogel is the most probable mechanism to boost the electrocatalytic activity.

Strain engineering of CoSA[sbnd]N[sbnd]C catalyst toward enhancing the oxygen reduction reaction activity

Developing efficient and cost-effective platinum-group metal-free (PGMF) catalysts for the oxygen reduction reaction (ORR) is crucial for energy conversion and storage devices. Among these catalysts, metal-nitrogen-carbon (MNC) materials, particularly cobalt single-atom catalysts (CoSANC), show promise as ORR electrocatalysts. However, their ORR activity is often hindered by strong hydroxyl (OH) adsorption on the Co sites. While the impact of strain engineering on MNC electrocatalysts has been minimally explored, recent studies suggest its potential to enhance catalytic performance and optimize intrinsic activity in traditional bulk catalysts. In this context, we investigate the effect of surface strain on CoSANC for ORR activity and correlate substrate-strain-induced geometric distortions with catalytic activity using experimental and theoretical methods. The findings suggest that the d-band center gap of spin states (Δεd) may be a preferred descriptor for predicting strain-dependent ORR performance in MNC catalysts. Leveraging CoSANC moiety placed on a substrate with an average size of 1.0 μm, we achieve performance comparable to that of commercial Pt/C catalysts when used as a cathode catalyst in zinc-air batteries. This investigation unveils the structure–function relationship of MNC electrocatalysts regarding strain engineering and provides valuable insights for future ORR activity design and enhancement.

Unraveling the phase transition and electrochemical application of MoSe2 material for energy conversion and storage devices

Layered transition metal selenides have garnered widespread attention as the potential non-noble metal-based materials to cater to diverse energy conversion and storage aspects. Therefore, we have implemented an integrated experimental and theoretical methodology to explore the application of molybdenum diselenide (MoSe2) for HER, OER, and supercapacitor avenues via employing nanostructural and surface engineering performance enhancement strategy. Herein, we have demonstrated the successful execution of a laboratory-scale electrolyzer for water splitting with a low cell voltage of 1.54 V at 10 mA cm−2 and 1.74 V at 50 mA cm−2 current rate for 50 h. This was accomplished using synthesized exfoliated conductive carbon enwrapped MoSe2-E/C material. Further, the DFT calculations revealed the origin of better electrochemical performance on MoSe2-E (103) plane. Moreover, MoSe2-E/C showcased a high capacitance of 734 F g−1 (@ 1 A g−1) and 472 F g−1 (@ 20 A g−1) in a three-electrode setup and symmetric cell configuration respectively along with capacity retention of 95.02 % at a current density of 10 A g−1 after 2000 cycles. Hence, the prepared material exhibited its pertinence for rendering distinctive energy-related challenges owing to its unique structural arrangement.

The Hybridization of Polymers with Metal Oxide Clusters for the Design of Non-Fluorinated Proton Exchange Membranes.

As the key component of various energy storage and conversion devices, proton exchange membranes (PEMs) have been attracting significant interest. However, their further development is limited by the high cost of perfluorosulfonic acid polymers and the poor stability of acid-dopped non-fluorinated polymers. Recently, a new group of PEMs has been developed by hybridizing polyoxometalates (POMs), a group of super acidic sub-nanoscale metal oxide clusters, with polymers. POMs can serve simultaneously as both proton sponges and stabilizing agents, and their complexation with polymers can further improve polymers' mechanical performance and processability. Enormous efforts have been focused on studying supramolecular complexation or covalent grafting of POMs with various polymers to optimize PEMs in terms of cost, mechanical properties and stabilities. This concept summarizes recent advances in this emerging field and outlines the design strategies and application perspectives employed for using POM-polymer hybrid materials as PEMs.

On-Demand Picoliter-Level-Droplet Inkjet Printing for Micro Fabrication and Functional Applications.

With the advent of Internet of Things (IoTs) and wearable devices, manufacturing requirements have shifted toward miniaturization, flexibility, environmentalization, and customization. Inkjet printing, as a non-contact picoliter-level droplet printing technology, can achieve material deposition at the microscopic level, helping to achieve high resolution and high precision patterned design. Meanwhile, inkjet printing has the advantages of simple process, high printing efficiency, mask-free digital printing, and direct pattern deposition, and is gradually emerging as a promising technology to meet such new requirements. However, there is a long way to go in constructing functional materials and emerging devices due to the uncommercialized ink materials, complicated film-forming process, and geometrically/functionally mismatched interface, limiting film quality and device applications. Herein, recent developments in working mechanisms, functional ink systems, droplet ejection and flight process, droplet drying process, as well as emerging multifunctional and intelligence applications including optics, electronics, sensors, and energy storage and conversion devices is reviewed. Finally, it is also highlight some of the critical challenges and research opportunities. The review is anticipated to provide a systematic comprehension and valuable insights for inkjet printing, thereby facilitating the advancement of their emerging applications.

Deciphering the enhanced oxygen reduction reaction activity of PrBa0.5Sr0.5Co1.5Fe0.5O5+δ via constructing negative thermal expansion offset for high-performance solid oxide fuel cell

Solid oxide fuel cells (SOFCs) are one of the most efficient energy conversion devices. However, the sluggish oxygen reduction reaction (ORR) kinetics at low temperatures significantly challenge the performance and commercialization of SOFCs. Introducing negative expansion coefficient materials has been recognized as an effective approach to enhancing the ORR catalytic properties, but a clear understanding of this enhanced electrochemical performance is still lacking. In this work, the composite cathode of PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) with different amounts of negative-thermal-expansion material Sm0.85Zn0.15MnO3 (SZM) is prepared, and in-depth analysis the effect of SZM on the catalytic activity of cathodic ORR is systematically investigated. Simultaneously, the mechanistic studies verify that the enhanced ORR activity might be attributed to the constructed compression strain during sintering, which significantly improves the adsorption, dissociation, and oxygen ion exchange process of the PBSCF cathode.

Eu-viologen based bimetal–organic frameworks nanosheets with Mn atoms anchored on Eu-µ-O skeletons as high-performance negative electrode for flexible asymmetric supercapacitors

Exploring advanced negative electrode materials is imperative to develop high-performance asymmetric supercapacitors for breaking through current energy density limits of supercapacitors, but remains challenging. Herein, a strategy is proposed to create a novel negative electrode by anchoring Mn single-atoms on Eu-viologen metal–organic frameworks (EV-Mn MOFs) nanosheets flowery architectures that self-supported on oxidized carbon cloths (OCC). Such EV-Mn/OCC achieves a negative broadened voltage window (−1 ∼ 0 V) and boosted areal capacitance (840.82 mF cm−2), which is four folds of the isostructural EV/OCC without Mn atoms and surpasses most of currently reported negative electrodes. Also, the EV-Mn/OCC manifests good cycling stability (∼80 % retention for 10,000 cycles). As deduced by the thorough studies of X-ray absorption fine spectra and X-ray photoelectron spectroscopies, the enhanced pseudocapacitance of EV-Mn/OCC definitely correlates to the valence modulation of Mn and Eu through internal electron transfer via Eu-O-Mn bonds on Eu-µ-O skeleton in EV-Mn MOFs. Subsequently, the constructed flexible all-solid-state symmetric supercapacitors employing EV-Mn/OCC as negative electrode can deliver a high energy density (86.89 μWh cm−2) at 1600 μW cm−2, outperforming many asymmetric devices based on traditional negative electrode materials. This work can spur the development of single-atom metallic electronic-modulation strategy for MOFs negative electrode material (MOFs-NEM), and accelerate their applications in flexible energy conversion and storage devices.

In-situ constructed NiCoZnS composite on nickel foam with hierarchical structures as bifunctional electrocatalysts for oxygen evolution reaction (OER) and supercapacitors

Transition metal sulfides have shown promise as candidates for energy storage and conversion devices, but the limited electroactive sites may greatly hinder further improvement. The novel nanostructured morphologies enhance active sites and surface area, thereby increasing overall electrochemical performance. Herein, we successfully synthesized various morphologies such as ZnS spheres, CoS star anise spice-like structures, and NiS flakes-like structures, which were directly grown on Ni foam using a single-step hydrothermal method. Additionally, the novel nanostructured morphologies were combined as a heterojunction NiCoZnS electrode to further utilize electronic and junction properties, thereby enhancing performance. This combination of morphologies—spheres, star anise spice, and flakes-like structures with ultrathin thickness and large surface areas—effectively increases the number of active sites, resulting in enhanced supercapacitor and oxygen evolution reaction (OER) performance. Moreover, directly growing nanostructures on conductive Ni foam endows the electrode materials with higher conductivity and richer active sites. In terms of supercapacitor performance, the NiCoZnS electrode exhibits a specific capacity of 1171.3 C g−1 at 0.5 A g−1 and remarkable rate performance. Furthermore, NiCoZnS maintains a capacitance retention of 94.9 % after 5000 cycles. As an electrocatalyst, NiCoZnS undergoes a rapid self-reconstruction process during the oxygen evolution reaction (OER), producing rich oxygen vacancies and thus demonstrating remarkable long-term stability. The NiCoZnS nanocomposites exhibit small overpotential (157 mV at 100 mA cm−2) and a Tafel slope of 128 mV dec−1. NiCoZnS's unique hierarchical nanostructures, doping-optimized electronic structural configuration, and specific surface lead to high catalytic performance. These remarkable performances of mixed morphologies like NiCoZnS hold great promise for energy storage and conversion devices.

Promoting Electrocatalytic Oxygen Reactions Using Advanced Heterostructures for Rechargeable Zinc-Air Battery Applications.

In order to facilitate electrochemical oxygen reactions in electrically rechargeable zinc-air batteries (ZABs), there is a need to develop innovative approaches for efficient oxygen electrocatalysts. Due to their reliability, high energy density, material abundance, and ecofriendliness, rechargeable ZABs hold promise as next-generation energy storage and conversion devices. However, the large-scale application of ZABs is currently hindered by the slow kinetics of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). However, the development of heterostructure-based electrocatalysts has the potential to surpass the limitations imposed by the intrinsic properties of a single material. This Account begins with an explanation of the configurations of ZABs and the fundamentals of the oxygen electrochemistry of the air electrode. Then, we summarize recent progress with respect to the variety of heterostructures that exploit bifunctional electrocatalytic reactions and overview their impact on ZAB performance. The range of heterointerfacial engineering strategies for improving the ORR/OER and ZAB performance includes tailoring the surface chemistry, dimensionality of catalysts, interfacial charge transfer, mass and charge transport, and morphology. We highlight the multicomponent design approaches that take these features into account to create advanced highly active bifunctional catalysts. Finally, we discuss the challenges and future perspectives on this important topic that aim to enhance the bifunctional activity and performance of zinc-air batteries.

A hybrid harvester using a magnetically coupled pendulum structure for limb movement

ABSTRACT Energy harvesting and conversion devices can provide power solutions for wearable devices. In this paper, a piezo-electromagnetic hybrid energy harvester (PEMHEH) using a magnetically-coupled pendulum structure for low-frequency limb movement is proposed. PEMHEH consists of a piezoelectric generator (PEG) unit including a main piezoelectric transducer, an auxiliary piezoelectric transducer (APT), and an electromagnetic generator (EMG) unit. It can reduce the starting frequency and increase the output performance by adopting a slidable mass block, the APT, and the rational magnetic pole arrangement. Its theoretical model is established, and magnetic simulation and experimental tests are carried out. The results show it can be started at 0.4 Hz excitation, and the output performance is maximized at 2 Hz. The maximum voltages of the piezoelectric generator and electromagnetic generator units are 5.29 V and 457 mV, and the maximum power is 286.16 μW (30 kΩ) and 11.25 μW (2 kΩ). The PEMHEH can light up LED boards at a 1 Hz excitation frequency. It has the potential to power wearable devices.

Effects of water on the degradations in the Ni-YSZ anode of the direct ammonia solid oxide fuel cells

Direct ammonia solid oxide fuel cells (DA-SOFCs) are promising next-generation energy conversion devices. Despite their possibilities, the electrochemical performance of DA-SOFCs degrade severely over long-term operation. However, the degradation mechanisms are still unveiled. Here, we reveal that the degradations of DA-SOFCs are significantly initiated by the presence of the water, which is the by-product of the SOFC operation, inside the fuel electrode. We measured the stability of the DA-SOFCs by varying the fuels and water partial pressure in the fuel. Thorough surface characterizations verified that Ni becomes favorable for oxidation when ammonia is present in the water, resulting in a reduction of the catalyst reactivity for NH3 decomposition and electric conductivity. Furthermore, we conducted a density functional theory calculation and found that N* adsorbed onto Ni decomposed from NH3 facilitates the H2O decomposition and results in nickel oxidation.

Rapid oxygen atom capture on perovskite surface boosting the activity and durability of cathode for solid oxide fuel cells

The content and distribution of surface oxygen vacancies are crucial for the oxygen reduction reaction (ORR) activity of solid oxide fuel cell (SOFC) cathodes. Therefore, a facile and rapid oxygen atom capture strategy is developed to modulate the surface oxygen vacancies of the cathode. By controlling the duration of NaBH4 solution reduction, precise modulation of the surface oxygen vacancies of NdBa0.5Sr0.5Co2O5+δ (NBSC) is achieved. Consequently, the processes of oxygen adsorption, dissociation, and diffusion on the surface of the NBSC cathode are enhanced. The research findings demonstrate that NBSC reduced for 10 min (RE-NBSC-10) exhibits optimal ORR catalytic activity and CO2 tolerance. At 800 °C, the Rp of RE-NBSC-10 decreases by 45 %, reaching 0.006 Ω‧cm2. Moreover, the maximum power density (MPD) of the RE-NBSC-10 cathode reaches 1.16 W cm−2, representing a 90.2 % improvement compared to NBSC. This research provides an efficient approach for the advancement of materials tailored for next-generation energy conversion devices.

Advanced hybrid membrane constructed with silicon carbide, graphene oxide and functionalized silicon carbide for vanadium permeability, proton conductivity to battery and fuel cell applications

The energy sector is currently exploring eco-friendly energy conversion and storage devices, as an alternative to traditional fossil fuel devices. A unique hybrid proton exchange membrane is developed for proton exchange membrane fuel cells (PEMFC) and vanadium redox flow battery (VRFB) application. Polymeric nanocomposite membranes are effective for the selective and controlled transportation of ions between the electrodes. This study utilizes various modifiers such as GO, SGO, SPES, and SiC, to modify the PES polymer matrix. Analysis of the functional groups confirmed the presence of modifiers and hydroxyl groups on the nanocomposite membrane. Additionally, the use of Field Emission Scanning Electron Microscopy (FESEM) validated the existence of honeycomb and sponge-like voids as well as the surface morphology on the membrane surface. The incorporation of modifiers into the nanocomposite membrane matrix serves as a reliable barrier for the transport of vanadium ions, leading to a significant reduction in vanadium ion permeability across the membrane. The mechanical properties and ion exchange capacity of nanocomposite membranes are enhanced, while the permeability of VO2+ decreases compared to that of the bare PES membrane. The enhancement of proton conductivity is further achieved with the utilization of modifiers in PES polymer. As compared to bare PES membrane, PES/SPES + SGO (5%) exhibits less than half the permeability for vanadium, and PES/SiC shows 44.03 % elongation means twice of bare PES membrane.

Accelerating the Development of Oxygen Electrodes for Solid Oxide Cells Using Two-Stage Machine Learning

Reversible Solid Oxide Cells (RSOCs) stand out as highly efficient and cost-effective devices for energy storage and conversion. However, the pursuit of high-performance and durable RSOCs is impeded by the lack of efficient and stable oxygen electrodes. The conventional trial-and-error approach used for the development of oxygen electrodes is resources and time-consuming. In this presentation, we introduce a novel "two-stage machine learning" approach designed to expedite the discovery of optimal oxygen electrodes for efficient oxygen reduction/evolution reaction (ORR/OER) in SOCs. In the initial stage, we employed a high-throughput calculation approach to generate four ORR/OER related descriptors (energy above the convex hull, p-band center, d-band center, and vacancy formation energy) for a set of 4455 perovskite oxide candidates. Subsequently, we successfully predicted these descriptors using machine learning techniques based on the fundamental physico-chemical features of the candidates. Moving to the second stage, we measured the polarization resistances - directly related to ORR/OER activity - of 142 oxygen electrodes and employed them as prediction targets. Through our machine learning method, we accurately predicted experimental results based on the fundamental physico-chemical features of the candidate materials. Notably, among the 4455 candidates studied, a specific oxygen electrode material is predicted to exhibit both high activity and stability. When applied to an RSOC based on a proton-conducting electrolyte operated at 600 °C, a high peak power density of >1.5 W cm−2 is demonstrated in the fuel cell mode, and a high current density of >2.5 A cm−2 is achieved at a cell voltage of 1.3 V in the water electrolysis mode while maintaining stable operation for 500 hours.